CVE-2025-39977: futex: Prevent use-after-free during requeue-PI
Noroxi assessment
Priority: Monitor (action score 31/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.15% (FIRST EPSS).
- Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
- Fixed version: Linux Linux 348736955ed6ca6e99ca24b93b1d3fbfe352c181, a170b9c0dde83312b8b58ccc91509c7c15711641, b549113738e8c751b613118032a724b772aa83f2; azl3 kernel 6.6.104.2-4 on Azure Linux 3.0 6.6.112.1-1.
Low priority for now. Upgrade to Linux Linux 348736955ed6ca6e99ca24b93b1d3fbfe352c181, a170b9c0dde83312b8b58ccc91509c7c15711641, b549113738e8c751b613118032a724b772aa83f2; azl3 kernel 6.6.104.2-4 on Azure Linux 3.0 6.6.112.1-1 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
In the Linux kernel, the following vulnerability has been resolved: futex: Prevent use-after-free during requeue-PI syzbot managed to trigger the following race: T1 T2 futex_wait_requeue_pi() futex_do_wait() schedule() futex_requeue() futex_proxy_trylock_atomic() futex_requeue_pi_prepare() requeue_pi_wake_futex() futex_requeue_pi_complete() /* preempt */ * timeout/ signal wakes T1 * futex_requeue_pi_wakeup_sync() // Q_REQUEUE_PI_LOCKED futex_hash_put() // back to userland, on stack futex_q is garbage /* back */ wake_up_state(q->task, TASK_NORMAL); In this scenario futex_wait_requeue_pi() is able to leave without using futex_q::lock_ptr for synchronization. This can be prevented by reading futex_q::task before updating the futex_q::requeue_state. A reference on the task_struct is not needed because requeue_pi_wake_futex() is invoked with a spinlock_t held which implies a RCU read section. Even if T1 terminates immediately after, the task_struct will remain valid during T2's wake_up_state(). A READ_ONCE on futex_q::task before futex_requeue_pi_complete() is enough because it ensures that the variable is read before the state is updated. Read futex_q::task before updating the requeue state, use it for the following wakeup.
- Published
- Oct 15, 2025
- Updated
- Nov 10, 2026
- EPSS
- 0.1% · 4th percentile
- CWE
- —
Report tools
Action score
31
Low priority for now.
- CVSS
- 31 / 40 · 7.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.1%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · Linux
- 7.8
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
Is your version affected? Check itNoroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
—
Versions reported by the vendor
Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.
Linux Linux
- 5.15affected
- 07d91ef510fb16a2e0ca7453222105835b7ba3b8 and later · before cb5d19a61274b51b49601214a87af573b43d60faaffected · git
- 07d91ef510fb16a2e0ca7453222105835b7ba3b8 and later · before 348736955ed6ca6e99ca24b93b1d3fbfe352c181affected · git
- 07d91ef510fb16a2e0ca7453222105835b7ba3b8 and later · before a170b9c0dde83312b8b58ccc91509c7c15711641affected · git
- 07d91ef510fb16a2e0ca7453222105835b7ba3b8 and later · before d824b2dbdcfe3c390278dd9652ea526168ef6850affected · git
- 07d91ef510fb16a2e0ca7453222105835b7ba3b8 and later · before b549113738e8c751b613118032a724b772aa83f2affected · git
- before 5.15not affected · semver
- 6.1.155 and later · up to and including 6.1.*not affected · semver
- 6.6.109 and later · up to and including 6.6.*not affected · semver
- 6.12.50 and later · up to and including 6.12.*not affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | linux | before 6.1.158-1 | 6.1.158-1 |
| Debian:13 | linux | before 6.12.57-1 | 6.12.57-1 |
| Debian:14 | linux | before 6.16.10-1 | 6.16.10-1 |
| openSUSE:Leap 16.0 | dtb-aarch64 | before 6.12.0-160000.9.1 | 6.12.0-160000.9.1 |
| openSUSE:Leap 16.0 | kernel-64kb | before 6.12.0-160000.9.1 | 6.12.0-160000.9.1 |
| openSUSE:Leap 16.0 | kernel-azure | before 6.12.0-160000.9.1 | 6.12.0-160000.9.1 |
| openSUSE:Leap 16.0 | kernel-default | before 6.12.0-160000.9.1 | 6.12.0-160000.9.1 |
| openSUSE:Leap 16.0 | kernel-default-base | before 6.12.0-160000.9.1.160000.2.6 | 6.12.0-160000.9.1.160000.2.6 |
| openSUSE:Leap 16.0 | kernel-docs | before 6.12.0-160000.9.1 | 6.12.0-160000.9.1 |
| openSUSE:Leap 16.0 | kernel-kvmsmall | before 6.12.0-160000.9.1 | 6.12.0-160000.9.1 |
| openSUSE:Leap 16.0 | kernel-obs-build | before 6.12.0-160000.9.1 | 6.12.0-160000.9.1 |
| openSUSE:Leap 16.0 | kernel-obs-qa | before 6.12.0-160000.9.1 | 6.12.0-160000.9.1 |
| openSUSE:Leap 16.0 | kernel-rt | before 6.12.0-160000.9.1 | 6.12.0-160000.9.1 |
| openSUSE:Leap 16.0 | kernel-source | before 6.12.0-160000.9.1 | 6.12.0-160000.9.1 |
| openSUSE:Leap 16.0 | kernel-syms | before 6.12.0-160000.9.1 | 6.12.0-160000.9.1 |
| openSUSE:Leap 16.0 | kernel-zfcpdump | before 6.12.0-160000.9.1 | 6.12.0-160000.9.1 |
| SUSE:Linux Enterprise Server 16.0 | kernel-azure | before 6.12.0-160000.9.1 | 6.12.0-160000.9.1 |
| SUSE:Linux Enterprise Server 16.0 | kernel-docs | before 6.12.0-160000.9.1 | 6.12.0-160000.9.1 |
| SUSE:Linux Enterprise Server 16.0 | kernel-kvmsmall | before 6.12.0-160000.9.1 | 6.12.0-160000.9.1 |
| SUSE:Linux Enterprise Server 16.0 | kernel-obs-qa | before 6.12.0-160000.9.1 | 6.12.0-160000.9.1 |
| SUSE:Linux Enterprise Server 16.0 | kernel-syms | before 6.12.0-160000.9.1 | 6.12.0-160000.9.1 |
| SUSE:Linux Enterprise Server 16.0 | kernel-zfcpdump | before 6.12.0-160000.9.1 | 6.12.0-160000.9.1 |
| SUSE:Linux Micro 6.2 | kernel-64kb | before 6.12.0-160000.9.1 | 6.12.0-160000.9.1 |
| SUSE:Linux Micro 6.2 | kernel-default | before 6.12.0-160000.9.1 | 6.12.0-160000.9.1 |
+4
Same product
linux: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation40Plan
- CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment40Plan
- CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()40Plan
Published before and after this one in the same product
- ← EarlierCVE-2025-39975Oct 15, 2025 · smb: client: fix wrong index reference in smb2_compound_op()39Monitor
- ← EarlierCVE-2025-39976Oct 15, 2025 · futex: Use correct exit on failure from futex_hash_allocate_default()31Monitor
- Later →CVE-2025-39978Oct 15, 2025 · octeontx2-pf: Fix potential use after free in otx2_tc_add_flow()31Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Linux Linux | 348736955ed6ca6e99ca24b93b1d3fbfe352c181 | Vendor (CNA) |
| Linux Linux | a170b9c0dde83312b8b58ccc91509c7c15711641 | Vendor (CNA) |
| Linux Linux | b549113738e8c751b613118032a724b772aa83f2 | Vendor (CNA) |
| Linux Linux | cb5d19a61274b51b49601214a87af573b43d60fa | Vendor (CNA) |
| Linux Linux | d824b2dbdcfe3c390278dd9652ea526168ef6850 | Vendor (CNA) |
| azl3 kernel 6.6.104.2-4 on Azure Linux 3.0 | 6.6.112.1-1 · CBL-Mariner Releases | Microsoft (MSRC) |
| debian:linux | 6.1.158-1 · Debian:12 | Package registry (OSV) |
| opensuse:dtb-aarch64 | 6.12.0-160000.9.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-64kb | 6.12.0-160000.9.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-azure | 6.12.0-160000.9.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-default | 6.12.0-160000.9.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-default-base | 6.12.0-160000.9.1.160000.2.6 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-docs | 6.12.0-160000.9.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-kvmsmall | 6.12.0-160000.9.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-obs-build | 6.12.0-160000.9.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-obs-qa | 6.12.0-160000.9.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-rt | 6.12.0-160000.9.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-source | 6.12.0-160000.9.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-syms | 6.12.0-160000.9.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| suse:kernel-64kb | 6.12.0-160000.9.1 · SUSE:Linux Micro 6.2 | Package registry (OSV) |
| suse:kernel-azure | 6.12.0-160000.9.1 · SUSE:Linux Enterprise Server 16.0 | Package registry (OSV) |
| suse:kernel-default | 6.12.0-160000.9.1 · SUSE:Linux Micro 6.2 | Package registry (OSV) |
| suse:kernel-default-base | 6.12.0-160000.9.1.160000.2.6 · SUSE:Linux Micro 6.2 | Package registry (OSV) |
| suse:kernel-docs | 6.12.0-160000.9.1 · SUSE:Linux Enterprise Server 16.0 | Package registry (OSV) |
| suse:kernel-kvmsmall | 6.12.0-160000.9.1 · SUSE:Linux Enterprise Server 16.0 | Package registry (OSV) |
| suse:kernel-obs-build | 6.12.0-160000.9.1 · SUSE:Linux Micro Extras 6.2 | Package registry (OSV) |
| suse:kernel-obs-qa | 6.12.0-160000.9.1 · SUSE:Linux Enterprise Server 16.0 | Package registry (OSV) |
| suse:kernel-rt | 6.12.0-160000.9.1 · SUSE:Linux Micro 6.2 | Package registry (OSV) |
| suse:kernel-source | 6.12.0-160000.9.1 · SUSE:Linux Micro 6.2 | Package registry (OSV) |
| suse:kernel-syms | 6.12.0-160000.9.1 · SUSE:Linux Enterprise Server 16.0 | Package registry (OSV) |
+1
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
—
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log (2)
- SSVC exploitation— → none
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (7 more)Show less
- git.kernel.org/stable/c/a170b9c0dde83312b8b58ccc91509c7c15711641
- git.kernel.org/stable/c/b549113738e8c751b613118032a724b772aa83f2
- git.kernel.org/stable/c/cb5d19a61274b51b49601214a87af573b43d60fa
- git.kernel.org/stable/c/d824b2dbdcfe3c390278dd9652ea526168ef6850
- cert-portal.siemens.com/productcert/html/ssa-019113.html
- cert-portal.siemens.com/productcert/html/ssa-082556.html
- cert-portal.siemens.com/productcert/html/ssa-457936.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.